Isn't this a mode of the D natural minor scale?

Please ignore my above post. I forgot that I had presented the original post's scale/mode in the key of 'A' not 'C.' Sorry.

It is an A dominant 7th Scale.Paul.

It can be used in that capacity, but "Dominant" implies a perfect 5th relationship with the tonal center. That's only one of several possible uses for the scale.

What it "is" is A Mixolydian.... a unique scale in it's own right that can just as easily used in a tonic capacity. That it happens to share a bond with D Major is only one of it's features.